title: Use of vertebroplasty to prevent proximal junctional fractures in adult deformity surgery: a biomechanical cadaveric study.
abstract: BACKGROUND
  Vertebral compression fractures at the proximal junction are common complications of long spinal fusion surgeries that can contribute to the development of proximal junctional kyphosis or proximal junctional failure. To our knowledge, no biomechanical studies have addressed the effect of vertebral augmentation at the proximal junction.
  
  
  OBJECTIVE
  To evaluate the effectiveness of prophylactic vertebroplasty in reducing the incidence of vertebral compression fractures at the proximal junction after a long spinal fusion in a cadaveric spine model.
  
  
  METHODS
  Biomechanical cadaveric study.
  
  
  METHODS
  We divided 18 cadaveric spine specimens into three groups of six spines each: a control group, a group treated with one-level prophylactic vertebroplasty at the upper instrumented vertebra, and a group treated with two-level prophylactic vertebroplasty at the upper instrumented vertebra and the supra-adjacent vertebra. In all spines, the pedicles were instrumented from L5 to T10. Using eccentric axial loading, the specimens were then compressed until failure. Failure was defined as a precipitous decrease in load with increasing compression. The effect of augmentation on load-to-failure was checked using linear regression. The effect of augmentation on incidence of adjacent fractures was checked using logistic regression. Differences at the level of p<.05 were considered significant. KyphX cement introducer was donated by Kyphon, and the pedicle screws were donated by DePuy.
  
  
  RESULTS
  Fractures occurred in 12 of 18 specimens: five in the control group, six in the one-level group, and only one in the two-level group; these differences were statistically significant.
  
  
  CONCLUSIONS
  Prophylactic vertebroplasty at the upper instrumented level and its supra-adjacent vertebra reduced the incidence of junctional fractures after long posterior spinal instrumentation in this axially loaded cadaveric model. Additional studies are necessary to determine if these results are translatable to clinical practice.
authors.affiliation: Division of Spine Surgery, Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA. Electronic address: ehenze1@jhmi.edu.
authors.forename: Khaled M
authors.initials: KM
authors.lastname: Kebaish
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Martin
authors.forename: Joseph R
authors.initials: JR
authors.lastname: O'Brien
authors.forename: Ivan E
authors.initials: IE
authors.lastname: LaMotta
authors.forename: Gabor D
authors.initials: GD
authors.lastname: Voros
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Belkoff
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D050815:Fractures, Compression / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016103:Spinal Fractures / Q000209:etiology / Q000517:prevention & control*; D013123:Spinal Fusion / Q000009:adverse effects*; D054854:Vertebroplasty
keywords: Complications; Long spinal fusion; Proximal junctional failure; Vertebral compression fracture; Vertebroplasty